Journal of Volcanology and Geothermal Research最新文献

{"title":"Life and death of a sinter archive: Evolution of siliceous hot-spring deposits (Holocene) on the dynamic Paeroa Fault at Te Kopia, Taupō Volcanic Zone, New Zealand","authors":"M.C. Rowe ,&nbsp;K.A. Campbell ,&nbsp;A. Hamilton ,&nbsp;Y. Jiang ,&nbsp;J. Pelser ,&nbsp;B. Murphy ,&nbsp;R. Martin ,&nbsp;K.M. Mackenzie ,&nbsp;D.A. Stallard ,&nbsp;B. Lyon ,&nbsp;A. Langendam ,&nbsp;E.E. Nersezova ,&nbsp;D.M. Guido ,&nbsp;J.V. Rowland","doi":"10.1016/j.jvolgeores.2025.108380","DOIUrl":"10.1016/j.jvolgeores.2025.108380","url":null,"abstract":"<div><div>Siliceous hot spring deposits, or sinter, host a variety of extremophile microorganisms in modern geothermal settings, and are often touted as an important candidate in the search for early life on Earth or elsewhere in the solar system. However, the preservation potential of microbial textures within silica may be compromised over geologic time scales, particularly in active tectonic and/or volcanic environments. The Te Kopia geothermal field, Taupō Volcanic Zone (TVZ), New Zealand, situated along the dramatic Paeroa Fault (with up to 500 m offset, and demarcating the eastern boundary of the central TVZ), provides a natural laboratory to investigate the preservation state of microbial textures/microfossils in young (&lt;5140 years BP) siliceous sinter that was originally deposited from circum-neutral alkali-chloride geothermal fluids (∼100 °C to ambient) discharging at the land surface. Since its formation, various processes – mechanical (landslides), biological (vegetation), chemical (acidic leaching) – have rapidly degraded the relict sinter. Combined field mapping and petrographic observations of sinter textures indicate a prolonged history of alkali-chloride fluid surface discharge, with multiple stages of fluid flow and changing flow directions over an expansive area, prior to a shift to acid-sulfate thermal fluid chemistry associated with a drop in the local water table, possibly related to fault activity. Mineralogy (X-ray diffraction) and in situ geochemistry (electron microprobe analysis, synchrotron X-ray fluorescence) illustrate the effects of acidic hydrothermal alteration, with accelerated recrystallization of opal-A to opal-CT and quartz, and the leaching and overprinting of geochemical tracers of sinter growth and microbial textures (e.g., Rb, Ga, Al, Fe). Results suggest that despite the proportionally minor amount of vent geyserite sinter compared to low-temperature palisade sinter in the study area, the dense nature of spring vent-related geyserite enhances its preservation potential compared to the more porous, filamentous microbial textures of the distal sinter apron-related palisade texture.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"465 ","pages":"Article 108380"},"PeriodicalIF":2.4,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144169301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stress drop behavior of the earthquakes associated with the September 19, 2021, La Palma volcanic eruption in Cumbre Vieja, Canary Islands (Spain)","authors":"J. Rueda ,&nbsp;J. Mezcua","doi":"10.1016/j.jvolgeores.2025.108370","DOIUrl":"10.1016/j.jvolgeores.2025.108370","url":null,"abstract":"<div><div>The stress drop of an earthquake is a key source parameter directly related to fault rupture dynamics. In the context of volcanic eruptions, such as the 2021 Cumbre Vieja event on La Palma Island, analyzing associated seismicity provides insights into variations in shear velocity, fault dimension, or effective normal stress. The local magnitudes (M_L) of the recorded volcano-tectonic events ranged from 0.3 to 4.1. To simulate the source properties, we used a theoretical point source model based on seismic wave response in a simplified medium. A spectral method was applied to 712 events with <span><math><msub><mi>M</mi><mi>L</mi></msub><mo>≥</mo><mn>2.5</mn></math></span>, selected from a total of 8488 events that occurred immediately before and during the eruption process. The estimated seismic moments ranged from 1.36 × 10¹² to 1.92 × 10¹⁵ Nm, and the corresponding stress drop values were in the range of 0.30–48.38 MPa. Two main seismic clusters were identified, one shallow located at the crust–mantle boundary at approximately 14 km depth and the other deep at 32–39 km depth. No significant depth dependence was observed in the stress drop values. The earthquakes associated with this volcanic eruption exhibited non-self-similarity, a behavior reported here for the first time in the context of volcanic earthquakes. The use of a normalized stress drop helped delineate the open conduit from the magma reservoir in the mantle in its way to the magma chamber also delineated with this parameter. Additionally, seismicity in the upper crust shows high normalized stress drop values at places where the magma ascent changes in direction.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"465 ","pages":"Article 108370"},"PeriodicalIF":2.4,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144169300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Feature analysis for the detection of P and S-wave arrival times in seismic signals from the Nevados del Chillán Volcanic Complex","authors":"Macarena Garay ,&nbsp;Millaray Curilem ,&nbsp;Jonathan Lazo ,&nbsp;Fernando Huenupan ,&nbsp;Daniel Basualto","doi":"10.1016/j.jvolgeores.2025.108350","DOIUrl":"10.1016/j.jvolgeores.2025.108350","url":null,"abstract":"<div><div>Very sophisticated machine learning tools are being developed for detecting P and S-waves in tectonic earthquakes, with excellent results, especially when approached from a recurrent perspective. However, their application to volcanic seismicity presents challenges due to the low magnitude, variability, and complexity of waveforms, caused by heterogeneous and anisotropic geological structures like magma chambers, rock types, and fractured zones. The proximity of sources to sensors often results in nearly simultaneous arrivals of P and S-waves. Additionally, volcanic areas are associated with high levels of seismic noise from non-volcanic sources. The specific characteristics of each volcano further necessitate adapting solutions to their unique dynamic behavior. Given these challenges, investigating signal preprocessing techniques that can improve P and S-wave detection in volcanic environments is essential. In this work, we studied seismic signals from the Nevados del Chillán volcanic complex to evaluate whether simple yet robust information could be provided to an LSTM model for effective P and S-wave detection. Our approach achieved 94% detection rate for P-waves and 91% for S-waves within a 0.5-second error margin, for 998 P and S-waves from the test set, improving detection accuracy and noise resilience over traditional methods.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"465 ","pages":"Article 108350"},"PeriodicalIF":2.4,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144138767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simulation of the 2012 Te Maari debris avalanche: Insight into the failure mechanics and the role of the hydrothermal system","authors":"Juliette Vicente ,&nbsp;Stuart Mead ,&nbsp;Gabor Kereszturi ,&nbsp;Craig Miller","doi":"10.1016/j.jvolgeores.2025.108351","DOIUrl":"10.1016/j.jvolgeores.2025.108351","url":null,"abstract":"<div><div>Composite volcanoes consist of alternating layers with varying mechanical properties, which contribute to the instability of the flanks. This instability can lead to the onset of mass flows down volcanic slopes, posing significant risks to nearby populations and infrastructures. Tongariro, an active andesite volcano, experienced one of New Zealand’s most recent debris avalanches at the Upper Te Maari crater on August 6, 2012. This debris avalanche, initiated simultaneously with a small-magnitude earthquake, released a volume of 7 × 10<span><math><msup><mrow></mrow><mrow><mn>5</mn></mrow></msup></math></span> m<span><math><msup><mrow></mrow><mrow><mn>3</mn></mrow></msup></math></span> of material from the source, which by unloading the pressurised vapour-dominated hydrothermal system, led to a phreatic eruption. This paper aims to better constrain the preparatory and triggering factors, along with the failure mechanics, that led to the 2012 debris avalanche. To achieve this, we applied slope stability finite-element modelling to assess the volcanic slope’s sensitivity to varying groundwater, seismic and mechanical conditions. Model results closely match the observed failure when considering the strength of hydrothermally altered rocks subjected to an increased pore pressure at shallow depth. We found that even a relatively minor rise in pore pressure, <span><math><mo>≈</mo></math></span> 250 kPa in the upper layers, could replicate the observed failure at Te Maari. Our simulations also reveal that this debris avalanche might be a multiple-stage failure involving the progressive sliding of two distinct blocks. These findings enhance our understanding of Tongariro’s structure and improve hazard assessments for future potential collapses at Tongariro and other New Zealand volcanoes.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"465 ","pages":"Article 108351"},"PeriodicalIF":2.4,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144138768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Eruptive chronology of the late Miocene Peñuela Volcanic complex formed during the early stage of activity of the Trans-Mexican volcanic belt","authors":"Julio César Andrade-Argueta ,&nbsp;Antonio Pola ,&nbsp;Denis Ramón Avellán ,&nbsp;José Luis Macias","doi":"10.1016/j.jvolgeores.2025.108362","DOIUrl":"10.1016/j.jvolgeores.2025.108362","url":null,"abstract":"<div><div>The Peñuela Volcanic Complex is in the central part of the Trans-Mexican Volcanic Belt (TMVB). It consists of volcanic domes emplaced over marine sedimentary successions from the Upper Jurassic to Upper Cretaceous periods. In this paper, we present a new geological map, stratigraphic, structural, and geochemical data of these domes. The Peñuela Volcanic Complex is made of two successions of dacitic and rhyolitic calc-alkaline rocks. New U<img>Pb zircon ages of these successions yielded 11.72 ± 0.61 and 10.71 ± 0.19 Ma (late Miocene). These ages correlate with the early stages of volcanic activity in the eastern sector of the TMVB. Volcanism in the region has been characterized by the emplacement of different successions of rocks ranging from andesitic to dacitic and rhyolitic, under a NW-SE oriented structures that occurred during the Miocene. The geochemical and petrographic analysis shows evidence of magmatic differentiation through a combination of assimilation and different degrees of fractional crystallization. These results suggest that the Peñuela Volcanic Complex is part of a broader Miocene magmatic episode in the TMVB, shaped by crustal assimilation, tectonic extension, and regional-scale migration of volcanic activity.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"465 ","pages":"Article 108362"},"PeriodicalIF":2.4,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144107126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Disequilibrium rheology of basaltic magma: Cooling deformation experiments with one-step and two-step cooling rates","authors":"E.M. Recchuiti ,&nbsp;Á. Höskuldsson ,&nbsp;A. Soldati","doi":"10.1016/j.jvolgeores.2025.108364","DOIUrl":"10.1016/j.jvolgeores.2025.108364","url":null,"abstract":"<div><div>Natural lavas cool via a combination of radiative, convective, and conductive heat loss. Radiative cooling dominates initially, followed by convective cooling as the flow develops a surface crust, while conductive cooling plays a minor role. Previous experimental rheological studies have not investigated the effect of changes in cooling rate, as would be expected with the transition in heat loss mechanism, and instead implemented one-step cooling rate protocols. This work represents the first step in replicating natural cooling rates in laboratory experiments and assessing their effect on lava rheology and its temporal evolution throughout flow emplacement. Cooling deformation experiments (CDEs) were carried out on a basaltic sample undergoing a constant shear rate of 1 s⁻¹ using one of two cooling protocols: one-step and two-step. The one-step cooling deformation experiments were run at 0.5, 1, 2, 3, 4, and 5 °C/min. The two-step cooling deformation experiments started with an initial (first-step) faster cooling rate and a later (second-step) slower cooling rate once the sample reached 1165 °C, specifically 1 → 0.5, 2 → 0.5, 3 → 0.5, 4 → 0.5, and 5 → 0.5 °C/min. Two-step CDEs result in more complex, three-stage viscosity trends. This work brings us closer to more accurately replicating the cooling dynamics of natural lavas and to furthering our understanding of their evolving rheology. Importantly, we find that lavas that experience two-step, faster-to-slower cooling histories are less viscous and can therefore flow faster than those that experience a one-step slow cooling history.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"465 ","pages":"Article 108364"},"PeriodicalIF":2.4,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144068611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magmatic system of the Kikai submarine caldera, SW Japan, imaged by passive seismic tomography","authors":"Yojiro Yamamoto ,&nbsp;Aki Ito ,&nbsp;Yasushi Ishihara ,&nbsp;Masayuki Obayashi ,&nbsp;Satoru Tanaka ,&nbsp;Haruhisa Nakamichi ,&nbsp;Hiroshi Yakiwara ,&nbsp;Yukihiro Nakatani ,&nbsp;Hiroko Sugioka ,&nbsp;Hironori Otsuka ,&nbsp;Tetsuo Matsuno","doi":"10.1016/j.jvolgeores.2025.108369","DOIUrl":"10.1016/j.jvolgeores.2025.108369","url":null,"abstract":"<div><div>The eruption of the Kikai caldera, located south of Kyushu in southwestern Japan, at 7.3 ka, was the largest volcanic eruption globally during the Holocene. Because of its offshore nature and sparse observational networks, the location and spatial extent of its current magma supply system remains unknown. We performed seismic tomography using data obtained from amphibious seismic observations to clarify the current magma supply system of the Kikai caldera based on its seismic velocity structure. A low-velocity zone was imaged in the crust just below the region inside the caldera rim within a 0–30 km depth. At a depth of 10 km, the P-wave velocity reduction rate was significant and the Vp/Vs ratio was low, suggesting the dominant presence of volatiles as supercritical fluid upwelling from the deep magma reservoir. Low S-velocity zones imaged at depths of 20–25 km were interpreted as deep magma reservoirs in the lower crust. Another low S-velocity region imaged at a depth of 15–20 km, approximately 20 km northeast of the caldera center, suggested the presence of another deep magma reservoir. The existence of multiple deep magmatic reservoirs is consistent with the interpretation of petrological studies of past eruptive activities. Furthermore, a low S-velocity region was imaged in the mantle wedge just above the area where intraslab earthquakes were active. Dehydration embrittlement in the slab mantle causes intraslab earthquakes and the generated fluids may flow from the slab into the mantle wedge, thereby forming a partial melting zone.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"465 ","pages":"Article 108369"},"PeriodicalIF":2.4,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144070815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anatomy of the fumarole field of Hakone Volcano, Japan: Interpretation of its resistivity structure and inferences for the steaming activity and recent hydrothermal eruption","authors":"Kazutaka Mannen ,&nbsp;Ryosuke Doke ,&nbsp;Akira Johmori ,&nbsp;George Kikugawa ,&nbsp;Takuto Minami ,&nbsp;Tetsuya Takahashi ,&nbsp;Mitsuru Utsugi ,&nbsp;Koichiro Fujimoto","doi":"10.1016/j.jvolgeores.2025.108363","DOIUrl":"10.1016/j.jvolgeores.2025.108363","url":null,"abstract":"<div><div>Understanding the underground structures of fumarole fields is essential for deciphering lethal hydrothermal eruptions and elucidating the chemical evolution of hydrothermal fluids en route to surface hot springs and steams. We implemented a controlled-source audio-frequency magnetotellurics (CSAMT) survey in Owakudani, the largest fumarole field on Hakone volcano, Japan. The hydrothermal system lies beneath a caprock structure, detected as a low-resistivity zone in two-dimensional electrical resistivity cross-sections. The caprock formed a plateau-like convexity with a diameter of approximately 500 m, centered on an inactive, forest-covered steaming area west of the 2015 hydrothermal eruption center. The caprock top subsided before the 2015 eruption, possibly because of depressurization of the hydrothermal system. Notably, local but distinctive high-resistivity zones exist within the caprock, especially in the southern part of the survey area, which contains major fumaroles and hot springs. Such zones, along with the high resistivity detected beneath the caprock, can be interpreted as vapor-dominated. Therefore, the fumaroles and hot springs in Owakudani overlie a two-layered vapor-dominated zone, with the upper layer located within the caprock and the lower layer beneath it. Classical works suggested that meteoric water heated by steam from the vapor-dominated zone of the hydrothermal system forms hot springs in the fumarole area. However, the chemical composition of the artificial hot spring—fromed from a steam and meteoric water—suggests simple mixing cannot explain its composition. Therefore, the two-layered vapor-dominated system beneath the fumarolic zone potentially contributes to the chemical differentiation of the hydrothermal fluid.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"465 ","pages":"Article 108363"},"PeriodicalIF":2.4,"publicationDate":"2025-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144107125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization of columnar- jointed intermediate to felsic volcanic rocks in eastern and southern China","authors":"Yongquan Li","doi":"10.1016/j.jvolgeores.2025.108365","DOIUrl":"10.1016/j.jvolgeores.2025.108365","url":null,"abstract":"<div><div>Columnar joints are widespread in basaltic lavas, where they have been extensively studied. Although rarer, they can also be found in intermediate and felsic volcanic rocks (IFVRs). In eastern and southern China, columnar joints are about 30 times more likely to be found in mafic lavas than in IFVRs, raising the question of their formation mechanisms. Detailed field observations and measurements are presented here for 11 Chinese intermediate to felsic volcanic fields. The comparatively high viscosities (i.e. relatively lower emplacement temperatures) usually reduce the formation probabilities of columnar joints in IFVRs. The formation of columnar joints is influenced by the cooling rate (or strain rate) which primarily controlled whether melts cross the glass transition temperature. The largely variable size (side length ∼ 10–161 cm) and ordering (Hexagonality Index ∼0.68–1.5) of columns in IFVRs are not directly associated with their major element compositions, but possibly are controlled by their textures, emplacement styles, and surrounding environments. High effusion rates of lavas and/or pyroclastic flows emplaced in flat areas (i.e., basin floor, caldera interior) through stagnant cooling processes (i.e. welding and/or devitrification) would be more likely to form columnar joints in IFVRs.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"465 ","pages":"Article 108365"},"PeriodicalIF":2.4,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144083952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Changes in seismicity in a volcanically active region of the Izu Peninsula, Japan","authors":"K.Z. Nanjo ,&nbsp;Y. Yukutake ,&nbsp;T. Kumazawa","doi":"10.1016/j.jvolgeores.2025.108355","DOIUrl":"10.1016/j.jvolgeores.2025.108355","url":null,"abstract":"<div><div>The eastern Izu Peninsula in Japan is volcanically and seismically active. Ordinary earthquakes frequently occurred at shallow depths in 2006 and 2009, when they clustered as swarms. Beneath ordinary earthquakes, low-frequency earthquakes (LFEs) were infrequently observed. To better understand the characteristics of those LFEs, we produced a LFE catalog for 2005–2020, using the matched-filter method. Timeseries analyses based on the Epidemic-Type Aftershock Sequence model showed quiescence, i.e., a change in occurrence rate, which became quiet. For comparison, the same analysis was conducted using the Japan Meteorological Agency catalog of ordinary earthquakes, and similar results were shown. The change points for both types of earthquakes fell during and after each of the swarms, revealing an earlier start of quiescence for shallow ordinary earthquakes than for deep LFEs. Surface displacement data obtained from the Geospatial Information Authority of Japan showed that the uplift was in abatement or unobservable during the study period. Our seismicity and geodetic results are interpretatively hypothesized as being associated with magmatic activity, as follows. When the absence of a supply of magma from a depth toward the crustal magma reservoir caused no significant uplift, magma intruded from this reservoir into the shallow crust, resulting in the 2006 and 2009 swarms. Due to this intrusion, stresses decreased in and around shallow parts of the reservoir and then quiescence for ordinary earthquakes began during or after each swarm. Due to this decrease, stresses in and around deep parts of it late decreased, delaying the start of quiescence of deep LFEs.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"465 ","pages":"Article 108355"},"PeriodicalIF":2.4,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143947368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}